Instruments

Burst Optical Observer and Transient Exploring System    

( A world wide Network of Robotic Telescopes )

2.The Wide Field Cameras (1998-2004)

Commercial Nikkor 50-mm wide-field lenses have been used, attached to two ST8 SBIG CCD cameras, similarly to the Optical Transiend Monitor (OTM) that was in operation at the Astronomical Institute in Ondrejov.

Each pair of the BOOTES wide-field cameras was mounted atop the 0.3-m LX 200 Meade telescope, allowing long integrations of a previously selected region. The four cameras monitor the same region of the sky, both in the I and V-bands. At the proposed locations, typical limiting magnitude is V = 12 for an integration time of 30 s, and V = 14 for 300 s.

 

Figure: One of the first images obtained by the BOOTE S-1 wide field camera covering the BATSE error box for GRB 980808, taken 66-min after the event.

The system is based on the digital signal processor board Photomate 20 Signal Processor Board which consists of two TMS320C40 processors operated by commercial PCs. The frames taken at each station at the very beginning the night will be loaded into memory (the primary frames). During the rest of the night, sucessive frames (secondary frames) could be compared with the primary frame.

If a real flash were detected in the secondary frames, the coordinates of the flashing object and the images themselves would be transferred to LAEFF-INTA. If the flash were indeed of cosmic origin, an object at an identical position should have also had been recorded in the second twin station. Hence such a configuration will allow to distinguish flashing objects closer than 1 million kms, therefore ruling out satellite glints and another atmospheric and near space background.

Exceptionally, when information on a GRB position would be obtained from the GCN (the GRB Coordinates Network), the cameras used to provide images of the corresponding GRB error boxes. In fact, such capability is proven to be very useful on the basis of the large size of GRB error boxes monitored in Ondrejov.